Designation:D1872-82NtiAMERICANSOCIETYFORTESTINGANDMATERIALS1916RaceSt.,Philadelphia,Pa.19103ReprintedfromtheAnnualBookofASTMStandards,CopyrightASTMIfnotlistedinthecurrentcombinedindex,willappearinthenextedition.StandardMethodofTestingMERCAPTOBENZOTHIAZOLEINBENZOTHIAZYLRUBBERCHEMICAL-FREE2-DISULFIDE’ThisstandardisissuedunderthefixeddesignationD1872;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(E)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thismethodcoversaprocedureforthemeasurementofthetoluene-solubleacidicim-puritiesinbenzothiazyldisulfide(MBTS).2.ApplicableDocument2.1ASTMStandard:D3040PracticeforPreparingPrecisionStatementsforStandardsRelatedtoRub-berandRubberTesting2NOTE1-ThespecificdatededitionofPracticeD3040thatprevailsinthisdocumentisreferencedinthePrecisionsection.3.SummaryofMethod3.1TheMBTSisdissolvedinhottolueneandcrystallizedoutbychillig.ThefilteredextractistitratedinanoneCdcousmedium,usingsodiummethoxideasthetitrantandthymolblueastheindicator.4.SignificanceandUse4.12-Mercaptobenzothiazole(MBT)isusu-allythemajorimpurityinMBTS.FreeMBTinMBTSmaybedeterminedbythismethod.4.2MBTandMBTSareusedforrubberandlatexvulcanizationacceleration.TheamountofMBTinMBTSmaybeofimpor-tanceinpredictingperformanceinrubbercom-poundsandforrawmaterialpurchaseandcontrol.4.3Thismethodmaybeusedasaquality-controltoolandforresearchanddevelopmentwork.5.Apparatus5.1IodineorErlenmeyerFlasks,250-cm3.5.2FilterFunnels,sinteredglass,medium5.3MagneticStirringApparatus.5.4Buret,semimicro,10-cm3.porosity,76-mm(3-in.).6.Reagents6.IPurityofReagents-Reagentgradechemicalsshallbeusedinalltests.Unlessotherwiseindicated,itisintendedthatallre-agentsshallconformtothespecificationsoftheCommitteeonAnalyticalReagentsoftheAmericanChemicalSociety,wheresuchspec-ificationsarea~ailable.~Othergradesmaybeused,provideditisfirstascertainedthatth...
